German Patent Application DE 10 2009 007 664 A1 describes a rotor blade for a turbomachine, including an airfoil for flow deflection, a blade root for attachment to a rotor of the turbomachine, an inner platform between the airfoil and the blade root, as well as a pocket defined by two axially spaced walls extending from the side of the platform opposite the airfoil toward the blade root. These walls are offset relative to a blade root edge toward a radial longitudinal axis for improved mechanical loading. The outer sides of these walls, which face away from the pocket, are parallel relative to the circumferential direction.
U.S. Pat. No. 4,595,340 also describes a rotor blade having an inwardly tapering pocket between an inner platform and a blade root for improved mechanical loading. The outer sides facing away from the pocket are also parallel relative to the circumferential direction.
As a result of the sloped, tapering inner sides and circumferentially parallel outer sides, the wall thickness increases in a circumferential direction toward the bottom of the pocket. An arrangement of two such pockets opposite each other in the circumferential direction results, in particular, in an accumulation of material in the region of the airfoil.